Fibrous products have been manufactured for many years using precious metal bushings, or feeders. Such feeders include a perforated bottom plate, or wall, commonly referred to in the art as a tip plate, which retains a pool of molten mineral material. Streams of molten mineral material issue from the openings, or tips, in the bottom bushing wall. By suitable means the streams of material are then attenuated and collected in the form of fibers.
The material feeders, or bushings, must be chemically resistant to the action of molten mineral material and must be dimensionally stable at high operating temperatures. Currently, such bushings are manufactured from elemental precious metals or binary alloys, such as, for example, platinum or platinum-rhodium alloys. Precious metals are very expensive. If bushings could be formed with smaller amounts of such precious metals or could be formed with less expensive materials, a tremendous economic advantage would be realized.
Another difficulty also encountered in the use of precious metal bushings stems from the fact that, after a period of time, precious metal bushings tend to creep or deform in service. Such creep or deformation adversely affects the quality of the fibers. The deformation requires the bushing to be removed from service earlier than if only the corrosive and erosive effects of the material had taken their toll on the bushing. Since the precious metal feeders have a limited life, there is a need in the art to provide for bushings that have an improved operating life.